The measurement of resistivity of semiconductor wafers is an essential part of the processing of such wafers. A number of different types of probes and probe mounts have been conventionally provided for making such measurements. Typical of probes of this nature are those of the type made and sold by Kulicke and Soffa Industries, Inc. of Horsham, Pa. and identified as Fell Resistivity Probe Head, and Kullicke and Soffa Disposable Probe Head. This company also produces the Model 3007A wafer locating resistivity probe base and the Model 5000 resistivity calculator, the latter including mounts for the Fell and disposable probe heads. Other companies which make mounts for probes of this type include Signatone Corporation of Santa Clara, Calif. and Macronetics, Inc. of Mountain View, Calif.
For the most part, the wafer engaging pins of conventional resistivity probes are shiftable relative to the heads which carry the probes. An explanation of the construction of conventional probes is set forth in the periodical, Solid State Technology, June 1969, in an article entitled "Mechanical Aspects of Testing Resistivity of Semiconductor Materials and Diffused Layers," by P. P. Clerx. In this article, it is made clear that the various pins of a probe head are shiftable relative to each other and have individual springs which bias the pins downwardly yet allow the pins to move upwardly when the lower ends of the pins engage selected locations on a semiconductor wafer whose resistivity is to be measured.
While the foregoing probe heads have been suitable for a number of different applications, they require extremely high accuracy in mounting and the use of individual springs for bias forces for seriously affecting their reliability so that the production costs have been relatively high. Since the pins experience wear and are often times having to be replaced, a need for a more economical way of mounting the pins and replacement of the probe has arisen to offset production and operational costs.